Since the enactment in Queensland of the Powers of Attorney Act 1998 (Qld) and the Guardianship and Administration Act 2000 (Qld), a decision can be made to withhold or withdraw life-sustaining medical treatment from an adult who lacks capacity to make such decisions for herself or himself. The Guardianship and Administration Tribunal of Queensland has been asked to consider the law in relation to these decisions on a number of occasions since the legislation was passed. This article explores the relevant provisions of these statutes and some of the difficulties that arise from how they are currently drafted. It also examines how the Guardianship and Administration Tribunal has dealt with applications to withhold or withdraw life-sustaining measures, and suggests a course that might avoid some of the difficulties that are inherent in Queensland's legislative regime.